"It's not nice to fool Mother Nature," according to the old commercial which promoted a brand of buttery-tasting margarine. But it's a lot healthier, judging from the trailblazing research underway at the Center for Human Nutrition.
CHN Director Scott Grundy's latest discovery of another "safe fat" is heartening news for the food industry as well as beef and chocolate-lovers. In their latest studies, Grundy and Dr. Andrea Bonanome showed that stearic acid, one type of saturated fat found in both beef and cocoa butter, does not raise cholesterol like other saturates. It apparently is quickly changed instead into healthier monounsaturated fat by the body.
Until now, many experts assumed that all kinds of saturated fats were bad for the heart because they clogged blood vessels with cholesterol. This new finding, published in the prestigious New England Journal of Medicine May 12, attracted major headlines across the nation. Once again, Dr. Grundy's search for the best and safest fats had far-reaching implications.
"Strictly speaking, we cannot condemn all saturated fats as unhealthy any longer," said Grundy. "It will be less confusing if we think of fats as either cholesterol-raising or cholesterol-safe. Stearic acid is a saturated fat, but it's not bad for you as we previously thought."
Grundy cautioned against reading the results as permission to indulge to excess in beef and chocolate. He still advised that people stick to widely accepted dietary guidelines and keep their fat intake low.
"Although beef fat will not raise cholesterol levels as much as many people assume, this does not mean we should overeat beef fat," said Grundy, noting beef also contains cholesterol-raising palmitic acid. And while the saturated fat in chocolate (cocoa butter) doesn't send cholesterol soaring as much as other commonly used saturated fats, you still shouldn't gorge on candy bars.
Grundy's study was based on 11 patients at the Dallas Veterans Administration Hospital who consumed three liquid diets high in either stearic acid, palmitic acid, or oleic acid. The first two are saturated and the last monounsaturated. The volunteers were given "pure" fatty acids not found in real foods. This method reduced the variables in the experiment, giving more definitive results.
In previous studies, Grundy found that the monounsaturated oleic acid lowers cholesterol when exchanged for palmitic. This time, Grundy discovered cholesterol levels also dipping for patients when stearic acid was substituted An accompanying NEJM editorial praised the value of Grundy's and Bonanome's research to the food industry. These new observations "underscore the reductionist process in biologic sciences and the challenge to incorporate new concepts into recommendations about public health," noted the Journal writers.
"The food industry surely will be interested to know that margarines high in stearic acid may be as efficacious in diets to lower cholesterol as are margarines rich in linoleic acid (a fatty acid found in corn oil) and may even taste more like butter than the margarines currently available," added the editorial.
Stearic acid also could be used to make a substitute for whipped cream as well as margarine and shortening for cooking. The beef industry meanwhile can act on this research to offer a greater variety of lean meats while still preserving the good taste and consistency consumers prefer. The emerging "gospel" according to Grundy about what fats are safe and unsafe continues to challenge previous nutritional dogmas. Grundy and Bonanome plan further tests of high stearic acid diets to determine any undesirable side effects.
"The aim of our research is to offer a wider choice of foods that can lower cholesterol because that makes it easier for people to stick to their diets," added Bonanome. In the meantime, butter, coconut oil, palm oil and palm kernel oil remain at the top of the list of harmful fats. Meat fat and cocoa butter rank some place in the middle while unsaturated oils like olive and safflower oils fall at the bottom of the list of harmful fats.
